Get a Google Account

Create a project for your client

Before you can send requests, you need to tell Google about your client and activate access to the API. You do this by using the Google API Console to create a project, which is a named collection of settings and API access information.

This API supports two types of credentials.
Create whichever credentials are appropriate for your project:

OAuth 2.0: Whenever your application requests private user
data, it must send an OAuth 2.0 token along with the request. Your
application first sends a client ID and, possibly, a client secret to
obtain a token. You can generate OAuth 2.0 credentials for web
applications, service accounts, or installed applications.

API keys:
A request that does not provide an OAuth 2.0 token must send an API
key.
The key identifies your project and provides API access, quota, and
reports.

The API supports several types of restrictions on API keys. If the API key that you
need doesn't already exist, then create an API key in the Console by
clicking Create credentials > API key. You can restrict the key before using it
in production by clicking Restrict key and selecting one of the
Restrictions.

Learn REST basics

If you decide not to use client libraries, you'll need to understand the basics of REST.

REST is a style of software architecture that provides a convenient and consistent approach to requesting and modifying data.

The term REST is short for "Representational State Transfer." In the context of Google APIs, it refers to using HTTP verbs to retrieve and modify representations of data stored by Google.

In a RESTful system, resources are stored in a data store; a client sends a request that the server perform a particular action (such as creating, retrieving, updating, or deleting a resource), and the server performs the action and sends a response, often in the form of a representation of the specified resource.

In Google's RESTful APIs, the client specifies an action using an HTTP verb such as POST, GET, PUT, or DELETE. It specifies a resource by a globally-unique URI of the following form:

https://www.googleapis.com/apiName/apiVersion/resourcePath?parameters

Because all API resources have unique HTTP-accessible URIs, REST enables data caching and is optimized to work with the web's distributed infrastructure.

You may find the method definitions in the HTTP 1.1 standards documentation useful; they include specifications for GET, POST, PUT, and DELETE.

REST in the QPX Express API

The QPX Express API operations map directly to REST HTTP verbs.

The specific formats for QPX Express API URIs are:

https://www.googleapis.com/qpxExpress/v1/resourcePath?parameters

The full set of URIs used for each supported operation in the API is
summarized in the Reference section.

Learn JSON basics

The QPX Express API returns data in JSON format.

JSON (JavaScript Object Notation) is a common, language-independent data format that provides a simple text representation of arbitrary data structures. For more information, see json.org.